MATHIAS GRÖN

EFFECTS OF HUMAN X AND Y
CHROMOSOMES ON ORAL
AND CRANIOFACIAL
MORPHOLOGY


Studies of 46,XY females, 47,XYY males and 45,X/
46,XX females

Abstract
The influence of the Xand Y chromosomes on the size and shape of the dental arches and occlusion
as well as on craniofacial cephalometric dimensions, angles and dimensional ratios is studied. The
material consists of Finnish patients with sex chromosome aneuploidies and normal population controls
from the “Kvantti Study” series, which was collected in the 1970´s and 1980´s at the Institute
of Dentistry, University of Turku. The patients are five individuals with complete testicular feminization
(CTF), eight 47,XYY males, and fourteen 45,X/46,XX females. The controls are population
female and male controls, as well as five first degree relatives of the individuals with CTF, three of
the 47,XYY males and nine of the 45,X/46,XX females studied. Dental arch dimensions and occlusion
as well as craniofacial cephalometric dimensions, angles and dimensional ratios are measured
fromdental study casts and standardized lateral cephalograms.
The results show that the presence of the Y chromosome in 46,XY females and the supernumerary
Y chromosomal gene(s) in 47,XYY males result in the enlargement of the dental arches and
craniofacial dimensions without substantial effects on dimensional ratios and plane angles, but with
special influence on the growth of the mandibular corpus. The reduction of X chromosomal genetic
material in 45,X/46,XX females results in the reduction of craniofacial dimensions, affecting
dimensional ratios and especially plane angles of the cranial base.


http://herkules.oulu.fi/isbn95142537...9514253744.pdf